'''Fitz''' (pronounced "fits") is a prefix in patronymic surname
s of Norman origin, that is to say originating in the 11th century. The word is a Norman language|Norman French noun
meaning "son of", from Latin ''filius'' (son), plus genitive case of the father's forename.
[Thus ''Robertus'', List of Latinized names|latinised form in the nominative case of the father's forename suggests his son's name in Latin as ''Filius Roberti'' ("son of Robert")]
Whilst ''Fitz'' is now the standard form used by modern historians the word appears in ancient documents with various spellings such as ''fiz'', ''filz'', etc. The word has developed in modern French to ''fils de'', with which it is thus cognate